from typing import Literal

from fastapi import Header, HTTPException
from pydantic import BaseModel


class AuthUser(BaseModel):
    username: str
    role: Literal["admin", "sensitive_admin"]


def issue_token(user: AuthUser) -> str:
    return f"dev-token::{user.username}::{user.role}"


def parse_token(token: str) -> AuthUser | None:
    parts = token.split("::")
    if len(parts) != 3 or parts[0] != "dev-token":
        return None

    username = parts[1]
    role = parts[2]
    if role not in {"admin", "sensitive_admin"}:
        return None

    return AuthUser(username=username, role=role)


def get_current_web_user(authorization: str | None = Header(default=None)) -> AuthUser:
    if not authorization or not authorization.lower().startswith("bearer "):
        raise HTTPException(status_code=401, detail="Missing bearer token")

    token = authorization[7:]
    user = parse_token(token)
    if user is None:
        raise HTTPException(status_code=401, detail="Invalid token")
    return user